The class of polymers of carbon monoxide and unsaturated hydrocarbon(s) has been known for a number of years. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical catalysts, e.g., peroxy compounds. U.K. patent No. 1,081,304 illustrates the production of such polymers of higher carbon monoxide content in the presence of alkylphosphine complexes of palladium salts as catalyst. Nozaki extended this process through the use of arylphosphine complexes of palladium salts and certain inert solvents.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon, also known as polyketones, has become of greater interest because of the greater availability of the polymers. The more recent process for the production of the polyketone polymers is illustrated by a number of published European patent applications including patent application Nos. 0,121,965 and 0,181,014. These publications describe a process employing a catalyst composition formed from a compound of the Group VIII metals palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa below 2 and a bidentate ligand of phosphorus, arsenic or antimony. Copending U.S. patent application Ser. No. 088,169, filed Aug. 21, 1987 describes a similar three component catalyst where the earlier bidentate ligand of two phosphorus atoms is replaced by a ligand of defined structure of one phosphorus atom and one nitrogen atom.
The linear alternating polyketone polymers have been shown to be of the general formula --CO--A-- where A is the moiety of ethylenically unsaturated hydrocarbon polymerized through the ethylenic unsaturation. By way of example, when the ethylenically unsaturated hydrocarbon is ethylene, the polymer is represented by the formula --CO--CH.sub.2 --CH.sub.2 . The polymers are relatively high molecular weight thermoplastics having utility in the production of shaped articles including containers for food and drink and parts for the automotive industry. The polymers are characterized by relatively high melting points, generally over 175.degree. C., frequently over 210.degree. C., depending upon the molecular weight and the chemical nature of the polymer.
Although the three-component catalyst system of Group VIII metal compound, anion of non-hydrohalogenic acid and bidentate ligand gives good yields of the polyketone polymer, it would be of advantage in some instances to provide for a less complex catalyst composition.